Ceran thermal expansion

Li20-Si02 (LAS). The trade names of such glass-ceramic matrix materials are Corningware, Zerodur and Ceran. This type of glass-ceramic matrix material has nearly zero thermal expansion and high thermal shock resistance. It is used for the production of optical and telescopic mirrors. 

Table3.l -19 Coefficient of linear thermal expansion a, density, and elastic properties of Zerodur and Ceran glass-ceramics...

The thermal expansion of many glass ceramic materials shows a non-linear temperature dependence. As indicated in Fig. 3.23, Ceran glass ceramic cooktop panels exhibit a parabolic function. 

To be able to take into consideration the non-linear curve of thermal expansion of Ceran glass ceramic cooktop panels with the temperature in our calculation, we introduce, instead of the coefficient of thermal expansion a, assumed as being constant in (3.5) to (3.7), the thermal expansion e. It is thus... 

With the temperature distributions in Fig. 3.25 at different times of the warming-up period, and with the curve of thermal expansion of Ceran glass ceramic cooktop panels with the termperature in Fig. 3.23, the stress distributions can be figured out. The temperature distributions in Fig. 3.25 were determined experimentally. 

Ceran cooktop panels are especially designed for small thermal expansions in the temperature range from 20 to 750 C. The thermal treatments during their production are optimized to reduce the compaction to a minimum. Thus, the level of stresses due to thermal expansion and compaction is low compared to the bending strength of the Ceran cooktops, which are not endangered by thermal and compaction stresses. 

Its virtually zero thermal expansion coefficient made this material interesting for other applications, too. The idea of using Zerodur for cookware soon came to mind. Trademarks, such as Pyroflam , Jena 2000 , Ceradur and Corning Vision produced by the main suppliers Corning Glassworks and Schott, are well-known cookware articles. At the end of the 1960s this product benefit led to the development of Ceran cooktop panels. 

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